htcacheclean - Clean up the disk cache

htcacheclean is used to keep the size of
mod_cache_disk's storage within a given size limit, or
limit on inodes in use. This tool can run either manually or in daemon mode.
When running in daemon mode, it sleeps in the background and checks the cache
directory at regular intervals for cached content to be removed. You can stop
the daemon cleanly by sending it a TERM or INT signal. When run manually, a
once off check of the cache directory is made for cached content to be
removed. If one or more URLs are specified, each URL will be deleted from
the cache, if present.

Daemonize and repeat cache cleaning every interval minutes.
This option is mutually exclusive with the -D, -v
and -r options. To shutdown the daemon cleanly, just send it
a SIGTERM or SIGINT.

-D

Do a dry run and don't delete anything. This option is mutually
exclusive with the -d option. When doing a dry run and
deleting directories with -t, the inodes reported deleted
in the stats cannot take into account the directories deleted, and will
be marked as an estimate.

-v

Be verbose and print statistics. This option is mutually exclusive
with the -d option.

-r

Clean thoroughly. This assumes that the Apache web server is
not running (otherwise you may get garbage in the cache). This option
is mutually exclusive with the -d option and implies
the -t option.

-n

Be nice. This causes slower processing in favour of other
processes. htcacheclean will sleep from time to time
so that (a) the disk IO will be delayed and (b) the kernel can schedule
other processes in the meantime.

-t

Delete all empty directories. By default only cache files are
removed, however with some configurations the large number of
directories created may require attention. If your configuration
requires a very large number of directories, to the point that
inode or file allocation table exhaustion may become an issue, use
of this option is advised.

-ppath

Specify path as the root directory of the disk cache. This
should be the same value as specified with the CacheRoot directive.

-Ppidfile

Specify pidfile as the name of the file to write the
process ID to when daemonized.

-Rround

Specify round as the amount to round sizes up to, to
compensate for disk block sizes. Set to the block size of the cache
partition.

-llimit

Specify limit as the total disk cache size limit. The value
is expressed in bytes by default (or attaching B to the
number). Attach K for Kbytes or M for
MBytes.

-Llimit

Specify limit as the total disk cache inode limit.

-i

Be intelligent and run only when there was a modification of the disk
cache. This option is only possible together with the -d
option.

-a

List the URLs currently stored in the cache. Variants of the same URL
will be listed once for each variant.

-A

List the URLs currently stored in the cache, along with their
attributes in the following order: url, header size, body size, status,
entity version, date, expiry, request time, response time, body present,
head request.

If htcacheclean is passed one or more URLs, each URL will
be deleted from the cache. If multiple variants of an URL exists, all
variants would be deleted.

When a reverse proxied URL is to be deleted, the effective URL is
constructed from the Host header, the
port, the path and the
query. Note the '?' in the URL must always be specified
explicitly, whether a query string is present or not. For example, an
attempt to delete the path / from the server
localhost, the URL to delete would be
http://localhost:80/?.

By passing the -a or -A options to
htcacheclean, the URLs within the cache will be listed
as they are found, one URL per line. The -A option
dumps the full cache entry after the URL, with fields in the
following order:

url

The URL of the entry.

header size

The size of the header in bytes.

body size

The size of the body in bytes.

status

Status of the cached response.

entity version

The number of times this entry has been
revalidated without being deleted.

date

Date of the response.

expiry

Expiry date of the response.

request time

Time of the start of the request.

response time

Time of the end of the request.

body present

If 0, no body is stored with this request,
1 otherwise.

head request

If 1, the entry contains a cached HEAD
request with no body, 0 otherwise.

htcacheclean returns a zero status ("true") if all
operations were successful, 1 otherwise. If an URL is
specified, and the URL was cached and successfully removed,
0 is returned, 2 otherwise. If an error
occurred during URL removal, 1 is returned.

Notice:This is not a Q&A section. Comments placed here should be pointed towards suggestions on improving the documentation or server, and may be removed again by our moderators if they are either implemented or considered invalid/off-topic. Questions on how to manage the Apache HTTP Server should be directed at either our IRC channel, #httpd, on Freenode, or sent to our mailing lists.